(1) Field of the Invention:
The present invention relates to an engine noise control device for use in the automobiles or the like which is a countermeasure against noise pollution. In particular, this invention relates to a device to reduce the engine noise radiated and/or diffracted to the outside from the engine compartment of the automobiles or the like.
(2) Description of the Prior Art:
In general, as shown in FIG. 1, an engine 1 of the automobile and the like is fitted onto frame side members 2 through mounts 3, and placed in an engine compartment 6 surrounded by a body 4 and a bonnet 5. The engine compartment 6 is opened to the atmosphere through an engine compartment opening 7 at the bottom portion of the engine compartment for radiating heat generated from the engine and so on. Thus, noise (non-controlled sound waves) generated from the engine 1 is radiated and/or diffracted to the outside from the engine compartment opening 7 as shown by a reference numeral 8, thereby causing noise pollution.
If the engine compartment opening is completely closed, such engine noises can be reduced to a large extent. However, since the engine compartment opening must not be closed for the above-mention reason, conventionally, a sound absorbing material has merely been sticked to the inner surface of the bonnet 5 and the other inner wall of the engine compartment 6, so that a large noise-reducing effect can not be obtained.